Mobile asphalt plant



July 19, 1960 E. o. MARTINSON MOBILE ASPHALT PLANT 2 Sheets-Sheet 1Filed Feb. 28, 1957 INVENTOR- BY [nnmv 0. MIT/Also ly 1960 E. o.MARTINSON 2,945,683

MOBILE ASPHALT PLANT 2 Sheets-Sheet 2 Filed Feb. 28, 1957 INVENTQR.

2! fro/May E g MOBILE ASPHALT PLANT Edwin o. Martinson, Brantford,Ontario, Canada, assignor to Koehring Company, Milwaukee, Wis., acorporation of Wisconsin Filed Feb. 28, 1957, Ser. No. 643,039 Claimspriority, application Canada Apr. 3, 1956 3 Claims. (Cl. 259-159) Thepresent invention relates generally to improvements in road buildingequipment, and relates more particularly to improvements in theconstruction and operation of mobile asphalt mixing plants.

Asphalt mixing plants are adapted to accurately proportion and tothoroughly mix the ingredients of the asphalt so as to insure asatisfactory product. While most of the larger and centrally locatedplants of this kind are of the stationary type, it has been found moreexpeditious and economical in cases where long hauls of the mixedasphalt are required to provide portable or mo- ,bile units capable ofproducing such mixtures at or near the point of use.

placing it in operating condition or in condition for road transport.

.A clear conception of the various features constituting the presentimprovement, and of the construct-ion and operation of atypicalcommercial mobile asphalt mixing plant embodying the invention, may behad by referring to the drawings accompanying and forming a part of thisspecification in which like reference characters designate the same orsimilar parts in the various views.

Fig. l is a perspective view of a mobile asphalt mixing plant built inaccordance with the invention and depicting the various parts incollapsed condition transported; 1

Fig. 2 is a diagrammatic opposite side elevation of a mixing plant,showing the same in assembled and installed condition in solid lines,and in knock-down transportable condition in dot-and-dash lines;

Fig. 3 is another perspective view of the complete mobile asphalt mixingplant of Fig. 1, showing the various parts assembled for operation;

Fig. 4 is an enlarged diagrammatic side elevation of the hot materialelevator only, showing the elevator operative position in solid linesand in transportlngposltion in dot-and-dash lines, and also showing indetail the mechanism which permits the quick shifting from one positionto the other without necessity for disconnecting the bucket chain.

Fig. 5 is an enlarged fragmentary side elevation similar as when being"ice to that'of Fig. 4, but showing only the boot or bottom section ofthe mineral dust elevator and the mechanism which permits that elevatorto be quickly moved from the operating to the transport position withoutnecessity .for breaking the bucxet chain. 1

Referring to the drawings, the improved self-contained, mobile, hot mix,batch type asphalt plant illustrated therein, comprises in general, atruss-type first "frame section or main frame 6 having transportingwheels 7 detachably associated therewith; an aggregate charging2,945,683 Patented July 19, 19 60 bin 8 mounted at one end of the frame6; a rotary drier and adapted to receive material from the bin 8 withthe aid of aconveyor 10; an aggregate screening, weighing, pulverizingand mixing unit 11 mounted within a second frame section or auxiliaryframe 12 pivotally secured to the end of the main frame 6 remote fom thefeed bin 8; a pair of laterally spaced bucket elevators- 13, 14interposed between the delivery end of the drier drum 9 and the unit 11and also being carried by the main frame 6; a dust collecting system 15mounted upon the frame 6 above the drier 9; and a driving engine 16 forthe various movable elements also supported on the truss frame 9 betweenthe elevators 13, .14.

The unitary main frame is constructed from structural bars and sheetiron with upper and lower decks 18, 19 respectively rigidlyinterconnected and reinforced by upright and inclined truss bars 20, andthe lower deck may have the wheels 7 detachably secured thereto in anysuitable, manner 'while being provided at its opposite ends withadjustable foot pads 21 adapted to serve as supports for the plant whenthe wheels 7 have been removed and the equipment is erected foroperation as in Fig. 3. i The charging bin 8 is preferably firmlymounted as low as possible at one extreme end of the frame 6 so that itwill provide sufficient head room for transportation clearance withoutremoval thereof and so that it will also tend to counterbalance any loadapplied to the opposite end of the main frame. The conveyor 10 may be ofthe endless belt or any other suitable type.

The rotary drier or processing means 9 has its drum provided withsupporting tires 23 rotatably cooperable with carrying rollers in a wellknown manner, and'this drier has internal material showering flighttherein and is also provided at its discharge end with a combustionchamber 24 as shown in Fig. 2. The drier 9 is confined between the upperand lower frame decks 18, 19 and is )adapted to be revolved by theengine 16 through a chain drive 25 as depicted in Figs.'1 and 3, and thehot heavier "aggregate delivered from the drier drum is discharged atits lower end into the lower fixed section 26 of the hot materialelevator 13. The'dust is withdrawn through a duct 27 from the upper endof this drum by a fan associated with the dust collecting and separatingsystem 15 which is mounted upon the upper main frame deck '18, and isdelivered into the lower fixed section 26 of the mineral dust elevator14.

; The aggregate treating unit or processingmeans 11 which is confinedwithin the auxiliary frame 12 is shown imposed screening, storing,weighing, and blending elements of the unit 11 are all of relativelywell known construction and operation, and are separated by suitableflow control gates for enabling the operator to accurately proportionthe ingredients of the product.

The auxiliary frame 12 which swingably supports the treating unit 11, isalso constructed of structural bar stock, and this frame 12 togetherwith the upper movable sections of the bucket elevators 13, 14 isswingably suspended fromthe adjacent end of the upper deck 18 of themain frame 6 by a pair of axially alined pivots 36, as shown in Figs. 1to 4 inclusive. This auxiliary frame is also provided with triangularbrackets 37 at its opposite sides which are pivotally connected by pivotpins 38 with the plungers 39 of adjacent hydraulic rams the cylinders 40of which are swingably secured to the upper deck 18 of the main frame 6by other pivot pins 41, and these "rams areoperable by liquid pressurederived from a pump carried by the plant to swing the frame 12 and theunit 11 together with the two upper elevator sections downwardly fortransportation as in Fig. l, and upwardly for normal operation as inFig. 3. These alternative positions are also illustrated in dot-and-dashand in solid lines in the diagram of Fig. 2. The frame 12 and unit 11being supported in cantilevered elevated vertical position by the ramswhen the device is in the operating position as in Fig. 3. At the lowerextremity of frame section 12 there is provided a fifth-wheel connection35 of well known construction for engagement with a truck tractor unitwhen the plant is to be moved.

It will be observed that except for the enclosed bucket elevators 13, 14all of the component parts of the asphalt plant are integrally mountedon either the main frame 6 or the frame extension 12. The bucketelevators are in part mounted on both parts of the frame and thusrequire a special construction to permit quick change of the plantbetween operating and transport conditions.

Generally, the housings for each of the elevators are divided into twoparts. The larger or so-called hot material elevator 13 has a bottom orboot section 26 which is rigidly mounted on the frame 6. This sectionincludes a drive shaft 43 on which a drive sprocket 48 is mounted fordriving the endless bucket chain 50. The top section 31 of this elevatorincludes a shaft 45 which is rotatably journalled in crossheads 46mounted on both sides of the housing for movement between guides 47. Abucket chain head pulley 49 is non-rotatably mounted on the shaft 45.The crossheads 46 are movably connected by a link 53 with the upperextremity of a connecting link 54 the lower end of which is secured tothe upper extremity of the fixed lower elevator section 26 by means of apivot pin 55. The lower extremity of each link 53 is also pivotallyattached to the upper end of an arm 56 the lower end of which isswingably secured to a bracket 57 attached to the adjacent elevatorsection 31.

This assemblage of elements is such that when the upper section 31 ofthe elevator 13 is raised into operative position as shown in solidlines in Figs. 2, 3 and 4, the crossheads 46 and the head pulley 49 willbe in uppermost position so as to place the chain 50 in stretched normaloperating condition. However, when the upper elevator section 31 of theelevator 13 is swung down as shown in dot-and-dash lines in Figs. 2 and4 and in solid lines in Fig. 1, so as to position this section and theunits 11 in approximately horizontal alinement with the drier 9, thenthe elevator bucket chain 50 will collapse and move the crossheads 46and the pulley 49 inwardly along the guideways 47 so as to permit thechain to slacken and bend around the pivot pins 36 without damaging thesame.

A somewhat different arrangement is used with the mineral dust elevator14 because of the relatively small and lightweight construction of itsbucket chain. In this elevator the housing sections 26 and 31 aresimilar to and mounted in the same way as the corresponding sections ofthe elevator 13. However, the head pulley arrangement is like the drivepulley arrangement shown in Fig. 4 for the hot material elevator, thehead pulley being driven by an extension of shaft 45 as shown in Fig. 3.Now referring to Fig. 5, to .prevent breaking the bucket chain 50 whenthe elevator sections are pivotally moved apart, the bottom pulley 48mounted on shaft 43 is arranged for vertical swinging movement by meansof a pivot 42* and arm 44 Its weight is such that it will normallymaintain the position shown in dotted lines. However when the topsection of the elevator 14 is moved forwardly and downwardly into thetravel position, the

it pulley 48 will be lifted against gravity into the position shown indot-and-dash lines.

When the various parts of the improved mobile asphalt plant have beenconstructed and assembled as hereinabove described, the entireassemblage may be safely transported by a suitable tractor from onelocality to another without danger of interfering with overheadobstructions. The lowering of the auxiliary frame 12 and its associatedparts may be quickly and readily effected with the aid of the hydraulicrams interposed on the opposite sides between the upper frame deck 18and the brackets 37.

When a desired destination has been reached, the foot rests 21 may becaused to coact with suitable mounting blocks as in Fig. 2 and thecarriage 7 may if desired be removed, whereupon the hydraulic rams maybe reversely actuated to raise the auxiliary frame 12, and the screenand pugmill assembly 11 together with the upper elevator sections 31, 31into operative position as illustrated in Figs. 2 and 3. The propellingmotor 16 which may be either an internal combustion engine or any othersuitable type, may be operated to revolve the drier 9, to actuate thefeed conveyor 10 and the elevators 13, 14 and to operate the dustingsystem and other auxiliary mechanisms. After the heater 24 has beenplaced in operation, successive batches of aggregate may be depositedwithin the supply bin 8 and delivered in regulated quantities andproportions to the revolving drier 9 wherein this aggregate isthoroughly heated and mixed and has excessive dust removed, the dustbeing withdrawn by the dust collecting system 15 which delivers theusable fines separated from the exhaust gases into the lower portion ofthe dust elevator 14.

The heavier aggregates after being properly treated in the drier 9 areultimately delivered in hot condition into the lower fixed section 26 ofthe elevator 13 and are conveyed upwardly and deposited upon thevibrating screen 29 mounted in the upper portion of the frame 12 wherethis coarser hot aggregate is separated into grades and is depositedinto the storage bins 32. The operator may then deliver the screenedmaterial in desired sizes and quantities to the weighing device 33 fromwhich it may be deposited into the pugmill'34 where regulated quantitiesof bitumen and the fines received from the system 15 may be added by theother elevator 14 and other ingredients may also be added to produce thedesired final mixture. The resultant product may thereafter be deliveredto vehicles positioned beneath the pugmill 34 and trucked away.

From the foregoing detailed description it should be apparent that thepresent invention provides a mobile, asphalt plant which is simple andcompact in construction, readily and safely transportable, andeffectively operable to produce accurately proportioned batches ofmixture in rapid succession. The assemblage provides a selfcontainedhighly mobile mixing plant in which a single attendant has full controlof every phase of plant operation at all times and can produce varioustypes of asphalt with utmost precision. All ingredients including thebitumen may be accurately weighed or measured and the pugmill 34 stirs,blends, kneads and thoroughly mixes the ingredients so as to insureproper coating of every particle with asphalt before final delivery ofthe product.

The assemblage for converting the improved plant from operativecondition to inactive position and vice versa is a very important partof the present invention since it enables the unit to be convenientlytransported with maximum headroom clearance, while still permitting theassemblage to be quickly set-up for normal operation. The sectionalelevators and the linkages associated with the elevator bucket rotorsupporting shafts 43, 45 enable the bucket chains to be either slackenedor distended without danger of damaging the same, and the lowering andraising of the auxiliary frame 12 with the aid of hydraulic rams effectssuch slackening and tensioning of the endless bucket carriersautomatically and with little effort on the part of the operator.

I claim:

1. A mobile asphalt plant comprising, in combination, a first framesection having material processing means thereon; a second frame sectionhaving material processing means thereon; means for conveying materialsbetween said first and said second sections; means for securing said twosections together to form a single frame unit'for transport; and meansfor supporting said second section in a cantilevered elevated verticalposition, said last mentioned means including means for swinging saidsecond section between its transport position and said elevatedposition.

2. A mobile asphalt plant comprising, in combination, a first framesection having aggregate drying means thereon; a second frame sectionhaving aggregate weighing and mixing means thereon, said second sectionbeing rigidly connectible to said first section in a horizontalpositionfor forming a single low elongated transportable structure;elevator means for transferring materials between said sections, saidelevator means having an upper portion foldable to a horizontaltransport position; and means for simultaneously swinging said secondsection and said elevator upper portion between said horizontaltransport position and an elevated vertical operating position, saidlast mentioned means adapted for supporting said second section incantilever fashion from said first section.

3. A mobile asphalt plant comprising,a unitary transportable framehaving an elongated drier mounted thereon, a charging bin for said driercarried by one end of said frame, a unit pivotally connected to theopposite end of said frame for receiving and further treating materiahdelivered from said drier, a collapsible elevator having a lower portioncarried on said frame and an upper portion carried by said unit fortransferring said material from said drier to said unit, and means forsupporting said unit in a cantilevered elevated position, said lastmentioned means also adapted for swinging both said unit and saidelevator upper portion between a horizontal position and said elevatedposition.

References Cited in the file of this patent UNITED STATES PATENTS520,185 Harrison May 22, 1894 854,734 Haines May 28, 1907 890,021 CampJune 9, 1908 1,548,014 Hetherington July 28, 1925 2,112,326 Berner Mar.29, 1938 2,190,044 Pollitz Feb. 13, 1940 2,298,160 Pollitz Oct. 6, 19422,493,898 Pollitz Jan. 10, 1950 2,706,623 Styes Apr. 19, 1955 2,766,871Arentzen Oct. 16, 1956 2,805,052 Preeman Sept. 3, 1957 FOREIGN PATENTS544,183 Germany Feb. 15, 1932

